The invention relates to an indirect-type air cooler, in which air, for example compressed charge air for an internal-combustion engine, is cooled by means of a liquid, wherein the air cooler is constructed from stacked pairs of plates having fins which are disposed therebetween, and the brazed stack is disposed in a housing into which the charge air flows, flows through the fins and exits the housing again, wherein said charge air exchanges heat with the liquid which flows in the plate pairs and which is introducible into the plate pairs via at least one inlet and via plate openings which are flush in the stack and is dischargeable via at least one outlet by means of other flush plate openings.
An indirect-type charge-air cooler having the features mentioned at the outset is disclosed in DE 10 2012 006 346 A1. While this document proposes a throughflow based on counterflow, on account of which remarkable heat-exchange efficiency may be achieved, there is need for further improvement in this respect.
Occasionally, gas bubbles, which have a negative effect on efficiency and often cause other disadvantages, are located in the coolant. This, of course, is not a novel type of problem. In general, this is addressed by employing venting pipes or by taking similar measures, for example disposing a separation wall having openings disposed at the top thereof, so that the gas bubbles can escape.
Gas bubbles or air bubbles have a particularly negative effect when, on account of a predefined installation position of a heat exchanger or on account of other reasons, the bubbles accumulate in a space which is flowed through by the liquid and can only be dissipated with difficulty or not at all.
The prior art which has been identified with reference to venting in the context of heat exchangers is disclosed in DE 28 40 813 C2, in DE 43 28 448 C2, in EP 257 111 A1, in DE 10 2005 005 043 A1, or in EP 075 750 B1, to name but a few such published documents.
In these published documents, heat exchangers which are typically employed as coolant coolers or else as heating heat exchangers are described. Said heat exchangers have a pipe-and-fin block, that is to say they do not have pairs of plates or a housing, and also accumulator boxes which are often rather voluminous which are disposed at opposite ends of the pipes. The mentioned venting pipes are typically disposed in one of the accumulator boxes and from there enable gas bubbles to escape from the coolant, or to be directed to an expansion tank where degassing is possible, respectively. A free cooling-air stream which is conveyed by a fan flows through the fins of such heat exchangers which, in contrast to indirect-type air coolers, are often disposed in the forward region of motor vehicles. In the case of EP 075 750 B1, the heat exchanger is a heater which is part of an air-conditioning system and which makes available a heating-air stream.